A Single Solenoid Based Double Actuator Device

ABSTRACT

A single solenoid based double actuator device 100 is disclosed having a first actuator 106 configured for linear movement between actuated and dropped positions along an axis of a winding 102 and biased towards dropped position, and a second actuator 120 arranged spaced apart from the first actuator 106 for linear movement between actuated and dropped positions and biased towards dropped position. A pair of magnetic paths, an upper magnetic path 130, and a lower magnetic path 132, is provided at two ends of the actuators such that first actuator, upper plate 130, second actuator 120 and lower plate 132 provide a magnetic path for a magnetic field generated on passing a current through the winding 102. On passing a current exceeding a first current value, through the winding, one of the actuators is actuated, and on the current exceeding a second current value, other actuator is also actuated.

TECHNICAL FIELD

The present disclosure relates generally to the field of solenoidactuators. In particular, the present disclosure pertains to anactuating device having two contacts actuated by a single solenoid.

BACKGROUND

Background description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

It is common to use solenoids for actuating a switch. A solenoid deviceincludes an electromagnetic coil, which generates magnetic flux when acurrent is passed through the coil. The generated magnetic flux is usedto attract a plunger towards a fixed core of the electromagnetic coil. Aspring member is disposed between the plunger and the fixed core. Whenpassage of current to the electromagnetic coil is stopped, the magneticforce decreases, and the plunger is moved away from the fixed core bythe biasing force of the spring member. Thus, by passing the currentthrough the electromagnetic coil, or discontinuing the current, theplungers can be moved linearly in forward/backward direction. The linearforward/backward movement of the plunger is used to actuate differentdevices, such as switches for turning them on/off, solenoid valves orrelays etc.

Many applications require actuation of more than one device, such assolenoid valves, and it becomes imperative to have as many solenoids asthe number of devices, which makes the equipment bulky on account ofmore space required to accommodate more solenoids, as well as increasescost of the equipment. To overcome the above problem, solenoid deviceshaving a single coil that actuates more than one valve actuator havebeen proposed.

For example, German Patent document DE10248143 discloses anelectromagnetic actuator having a sleeve-shaped or tubular yoke, inwhich permanent magnets and a coil are arranged adjacent to one anotherin an annular arrangement along a longitudinal axis of the yoke. Thecoil and the permanent magnets are arranged in a bobbin of tubularshape, and has a through hole extending along the longitudinal axis. Twoarmatures are guided within the through hole of the bobbin for linearmovement along the longitudinal axis. The permanent magnets set up amagnetic field, which draws the two armatures together against a forceof return springs that act to push the armatures away from each other.The coil may set up a field in the other direction such that the forcedue to the permanent magnets is overcome to push the armatures apart.The armatures have fastening rods on their outer ends to transfer forcedue to the coil to the devices to be actuated.

The cited patent reference discloses a single coil based double actuatordevice where the actuators are arranged in collinear fashion. However,in certain applications, it may not be possible to arrange the twoactuators in collinear manner.

United States Patent application number 20130222089A1 discloses solenoiddevice having a first electromagnetic coil; first and second plungersmovable on energization of the first electromagnetic coil; first andsecond fixed cores respectively facing the first and second plungers;and a yoke. When the first electromagnetic coil is not energized, firstand second gaps are formed between the first and second plungers and therespective first and second fixed cores. When the first electromagneticcoil is energized, the magnetic flux flows in a first magnetic circuit,provided by the first plunger, the first fixed core and the yoke, viathe first gap, and a second magnetic circuit, provided by the first andsecond plungers, the first and second fixed cores and the yoke, via thefirst and second gaps, so that the first and second plungers areattracted toward the first and second fixed cores. However, since thefirst magnetic circuit passes through only the first gap, and the secondmagnetic circuit passes through both of the first and second gaps,larger amount of the magnetic flux flows in the first magnetic circuitwhich results in stronger magnetic force on the first plunger to actuatethe first plunger before the second plunger. The cited patent referencediscloses a complex structure to configure two magnetic circuits suchthat strength of the magnetic flux in the respective circuits depends onnumber of gaps in the respective circuits.

It would therefore be advantageous to provide an improved singlesolenoid double actuator device that does not require the two actuatorsto be in collinear arrangement and is simple in construction.

OBJECTS OF THE INVENTION

A general object of the present disclosure is to provide a singlesolenoid double actuator device that overcomes drawback of knowndevices.

An object of the present disclosure is to provide a single solenoiddouble actuator device that does not require the two actuators to be incollinear arrangement.

Another object of the present disclosure is to provide a single solenoiddouble actuator device that allows actuation of the two actuators insequential manner.

Yet another object of the present disclosure is to provide a singlesolenoid double actuator device that uses a single magnetic path toactuate the two actuators.

Still another object of the present disclosure is to provide a singlesolenoid double actuator device that consumes less power by enablingactuation of the two actuators by current pulses.

SUMMARY

Aspects of the present disclosure relate to a solenoid actuation device.In an aspect, the proposed solenoid actuation device incorporates asingle solenoid coil (also referred to as solenoid winding, or simply aswinding, or as coil, and all the terms used interchangeably hereinafter)but two actuator plungers that are actuated at two different currentvalues passed through the coil. In another aspect, the two actuatorplungers of the disclosed device are arranged generally in parallelconfiguration spaced apart from each other, thereby overcominglimitation of the known devices that require the two actuator plungersto be arranged in collinear fashion, which may not be possible incertain applications.

In one embodiment, the proposed single solenoid based double actuatordevice includes a solenoid winding having an opening along an axis ofthe solenoid winding and a first actuator plunger configured through theopening for linear movement along the axis of the solenoid windingbetween an actuated position and an unactuated position, referred to inthe art as dropped position and the two terms used interchangeablyhereinafter. The first actuator plunger is biased by a first biasingforce to remain in the dropped position.

The device further includes a pair of magnetic paths having an uppermagnetic path located at an upper end of the solenoid winding, and alower magnetic path located at a lower end of the solenoid winding.

A second actuator plunger is arranged for linear movement between anactuated position and an dropped position along a second actuator axis,and is biased by a second biasing force to remain in the droppedposition. The second actuator is arranged between the upper magneticpath and the lower magnetic path such that the second actuator axis isspaced apart from the axis of the solenoid winding.

In an aspect, the first actuator plunger, the upper magnetic path, thesecond actuator plunger and the lower magnetic path provide a magneticpath for a magnetic field created as a result of passing of a currentthrough the solenoid winding; and in another aspect, the first biasingforce, the second biasing force and the magnetic path is configured suchthat when the current through the solenoid winding exceeds a firstcurrent value, one of the first actuator plunger and the second actuatorplunger is moved to the corresponding actuated position overcoming thecorresponding biasing force, and when the current through the solenoidwinding exceeds a second current value, which is higher than the firstcurrent value, other of the first actuator plunger and the secondactuator plunger is also moved to the corresponding actuated positionovercoming the corresponding biasing force.

The first biasing force may be higher than the second biasing force, andwhen the current through the solenoid winding exceeds the first currentvalue, the first actuator plunger may move to its actuated positionovercoming the first biasing force. When the current through thesolenoid winding exceeds the second current value, the second actuatorplunger may move to the corresponding actuated position overcoming thesecond biasing force.

The first biasing force may be provided by a first spring configuredbetween a collar on the first actuator plunger and the first guide tobias the first actuator plunger in a direction towards the lowermagnetic path.

The second biasing force may be provided by a second spring configuredbetween the second actuator plunger and the upper magnetic path to biasthe second actuator plunger in the direction towards the lower magneticpath.

In an embodiment, actuation of the first actuator plunger at a lowercurrent and actuation of the second actuator plunger at a higher currentmay be achieved by providing two magnetic paths such that the firstactuator plunger is part of both the magnetic paths but the secondactuator plunger is part of only one of the two magnetic paths. Thefirst actuator plunger being part of two magnetic paths is subjected tohigher magnetic force and therefore may get actuated at lower currentthrough the coil, and the second actuator plunger being part of only oneof the two magnetic paths, is subjected to lower magnetic force andtherefore shall get actuated at higher current through the coil.

To achieve two magnetic paths, the upper magnetic path and the lowermagnetic path may be coupled to each other by a connecting portionlocated between the second actuator plunger and the solenoid winding.The connecting portion may provide a secondary magnetic path through thefirst actuator plunger, a part of the upper magnetic path, theconnecting portion and a part of the lower magnetic path.

When the current through the solenoid winding exceeds the first currentvalue, only the first actuator plunger may move to the correspondingactuated position overcoming the corresponding biasing force on accountof higher magnetic force from combination of magnetic fields through themagnetic path formed by the first actuator plunger, the upper magneticpath, the second actuator plunger and the lower magnetic path, and thesecondary magnetic path formed by the first actuator plunger, a part ofthe upper magnetic path, the connecting portion and a part of the lowermagnetic path.

When the current through the solenoid winding exceeds the second currentvalue, the second actuator plunger may also move to the correspondingactuated position overcoming the corresponding biasing force on accountof magnetic force from comparatively weaker magnetic field through thesecondary magnetic path formed by the first actuator plunger, a part ofthe upper magnetic path, the connecting portion and a part of the lowermagnetic path.

In another embodiment, a single solenoid based double actuator device isdisclosed, wherein the axis of the solenoid is separated from axis offirst actuator and the second actuator. The device includes a solenoidwinding having an opening along an axis of the solenoid winding and aconnecting static pole located along the axis of the solenoid windingthrough the opening, a pair of magnetic paths having an upper magneticpath located at an upper end of the connecting static pole, and a lowermagnetic path located at a lower end of the connecting static pole. Afirst actuator plunger is arranged for linear movement between anactuated position and an dropped position along a first actuator axisbetween the upper magnetic path and the lower magnetic path, and asecond actuator plunger is arranged for linear movement between anactuated position and an dropped position along a second actuator axisbetween the upper magnetic path and the lower magnetic path. The firstactuator plunger is biased by a first biasing force to remain in thedropped position, and the second actuator plunger is biased by a secondbiasing force to remain in corresponding dropped position.

The first actuator plunger and the second actuator are arranged betweenthe upper magnetic path and the lower magnetic path such that the firstactuator axis and the second actuator axis are spaced apart from theaxis of the solenoid winding.

In an aspect, the connecting static pole, the upper magnetic path, thefirst actuator plunger, the static pole and the lower magnetic pathprovide a first magnetic path for a magnetic field created as a resultof passing of a current through the solenoid winding, and the connectingstatic pole, the upper magnetic path, the second actuator plunger, andthe lower magnetic path provide a second magnetic path for the magneticfield created as a result of passing of a current through the solenoidwinding.

In an aspect, the first biasing force, the second biasing force, thefirst magnetic path and the second magnetic path are configured suchthat when the current through the solenoid winding exceeds a firstcurrent value, one of the first actuator plunger and the second actuatorplunger is moved to the corresponding actuated position overcoming thecorresponding biasing force, and when the current through the solenoidwinding exceeds a second current value, which is higher than the firstcurrent value, other of the first actuator plunger and the secondactuator plunger is also moved to the corresponding actuated positionovercoming the corresponding biasing force.

The solenoid axis may be located between the first actuator axis and thesecond actuator axis.

In yet another embodiment of the disclosure, a single solenoid baseddouble actuator device is disclosed, wherein the first biasing force isprovided by a combination of a first permanent magnet and a first springconfigured with the first actuator plunger, and the second biasing forceis provided by a combination of a second permanent magnet and a secondspring configured with the second actuator plunger.

The magnetic field generated as a result of passing of a current throughthe solenoid winding, either supports or nullifies magnetic fields ofthe first permanent magnet and the second permanent magnet, whichchanges the net biasing force on the corresponding actuator plunger suchthat when the current through the solenoid winding exceeds a firstcurrent value in one direction, one of the first actuator plunger andthe second actuator plunger is moved to the corresponding actuatedposition. When the current through the solenoid winding exceeds a secondcurrent value, which is higher than the first current value, other ofthe first actuator plunger and the second actuator plunger is also movedto the corresponding actuated position overcoming even the secondbiasing force.

The first permanent magnet and the second permanent magnet may beconfigured such that the respective magnetic fields are in oppositedirections, in which case the magnetic field generated as a result ofpassing of a current through the solenoid winding shall add to themagnetic field of the one of the two permanent magnets and shall nullifythe magnetic field of the other of the two permanent magnets. When acurrent exceeding the first current value is applied through thesolenoid winding in a first direction one of the first actuator plungerand the second actuator plunger shall move to the corresponding actuatedposition. On the other hand, when a current exceeding the second currentvalue is applied through the solenoid winding in a second direction thatis opposite the first direction, other of the first actuator plunger andthe second actuator plunger shall be moved to the corresponding actuatedposition. When the current in the second direction is increased, boththe actuator plungers are moved to the corresponding actuated position.

In yet another embodiment, a single solenoid based double actuatordevice is disclosed, wherein the first biasing force is provided by acombination of a first permanent magnet and a first spring configuredwith the first actuator plunger, and the second biasing force isprovided by a combination of a second permanent magnet and a secondspring configured with the second actuator plunger. The two permanentmagnets and the corresponding springs are configured such that magneticforce on the first actuator plunger and the second actuator plunger fromthe respective permanent magnets partly nullifies the force from thecorresponding springs

The magnetic field generated as a result of passing of a current throughthe solenoid winding, either supports or nullifies magnetic fields ofthe first permanent magnet and the second permanent magnet to change thenet biasing force on the corresponding actuator plunger such that whenthe current through the solenoid winding exceeds a first current value,one of the first actuator plunger and the second actuator plunger ismoved to the corresponding actuated position, and when the currentthrough the solenoid winding exceeds a second current value, other ofthe first actuator plunger and the second actuator plunger is also movedto the corresponding actuated position.

Each of the first actuator plunger and the second actuator plunger andthe corresponding permanent magnets are configured for latching of thefirst actuator plunger and the second actuator plunger in thecorresponding actuated positions such that after the current through thesolenoid winding is stopped, the first actuator plunger and the secondactuator plunger remain in the respective actuated positions, whichenables actuation of the device by applying current pulses.

The first permanent magnet and the second permanent magnet may beconfigured such that the respective magnetic fields are in oppositedirections, and the magnetic field generated as a result of passing of acurrent through the solenoid winding adds to the magnetic field of theone of the two permanent magnets and nullifies the magnetic field of theother of the two permanent magnets. When a current pulse exceeding thefirst current value is applied through the solenoid winding in a firstdirection, one of the two actuator plungers is moved to thecorresponding actuated position, and when the current pulse exceedingthe second current value is applied through the solenoid winding in theopposite direction, the other actuator plunger is also moved to thecorresponding actuated position.

The second current value of the second pulse applied in the oppositedirection may be lower than the first current value so that the firstactuator plunger does not move to the dropped position.

Various objects, features, aspects and advantages of the inventivesubject matter will become more apparent from the following detaileddescription of preferred embodiments, along with the accompanyingdrawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the present disclosure, and are incorporated in andconstitute a part of this specification. The drawings illustrateexemplary embodiments of the present disclosure and, together with thedescription, serve to explain the principles of the present disclosure.

FIG. 1 illustrates an exemplary representation of the proposed singlesolenoid based double actuator device having a single magnetic path, inaccordance with embodiments of the present disclosure.

FIG. 2A illustrates an exemplary representation of the single solenoidbased double actuator device of FIG. 1 showing a first actuator plungerin actuated position, in accordance with embodiments of the presentdisclosure.

FIG. 2B illustrates an exemplary representation of the single solenoidbased double actuator device of FIG. 1 showing both the actuatorplungers in actuated position, in accordance with embodiments of thepresent disclosure.

FIG. 3 illustrates an exemplary representation of the single solenoidbased double actuator device having two magnetic paths, in accordancewith embodiments of the present disclosure.

FIG. 4 illustrates an exemplary representation of the proposed singlesolenoid based double actuator device having axis of the solenoidseparated from axis of first actuator and the second actuator, inaccordance with embodiments of the present disclosure.

FIG. 5A illustrates an exemplary representation of the single solenoidbased double actuator device of FIG. 4 showing a first actuator plungerin actuated position, in accordance with embodiments of the presentdisclosure.

FIG. 5B illustrates an exemplary representation of the single solenoidbased double actuator device of FIG. 4 showing both the actuatorplungers in actuated position, in accordance with embodiments of thepresent disclosure.

DETAILED DESCRIPTION

The following is a detailed description of embodiments of the disclosuredepicted in the accompanying drawings. The embodiments are in suchdetail as to clearly communicate the disclosure. However, the amount ofdetail offered is not intended to limit the anticipated variations ofembodiments; on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the present disclosure as defined by the appended claims.

All publications herein are incorporated by reference to the same extentas if each individual publication or patent application werespecifically and individually indicated to be incorporated by reference.Where a definition or use of a term in an incorporated reference isinconsistent or contrary to the definition of that term provided herein,the definition of that term provided herein applies and the definitionof that term in the reference does not apply.

In some embodiments, the numbers expressing quantities of ingredients,properties such as concentration, reaction conditions, and so forth,used to describe and claim certain embodiments of the invention are tobe understood as being modified in some instances by the term “about.”Accordingly, in some embodiments, the numerical parameters set forth inthe written description and attached claims are approximations that canvary depending upon the desired properties sought to be obtained by aparticular embodiment. In some embodiments, the numerical parametersshould be construed in light of the number of reported significantdigits and by applying ordinary rounding techniques. Notwithstandingthat the numerical ranges and parameters setting forth the broad scopeof some embodiments of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspracticable. The numerical values presented in some embodiments of theinvention may contain certain errors necessarily resulting from thestandard deviation found in their respective testing measurements.

As used in the description herein and throughout the claims that follow,the meaning of “a,” “an,” and “the” includes plural reference unless thecontext clearly dictates otherwise. Also, as used in the descriptionherein, the meaning of “in” includes “in” and “on” unless the contextclearly dictates otherwise.

The recitation of ranges of values herein is merely intended to serve asa shorthand method of referring individually to each separate valuefalling within the range. Unless otherwise indicated herein, eachindividual value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g. “such as”) provided with respectto certain embodiments herein is intended merely to better illuminatethe invention and does not pose a limitation on the scope of theinvention otherwise claimed. No language in the specification should beconstrued as indicating any non-claimed element essential to thepractice of the invention.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each groupmember can be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. One ormore members of a group can be included in, or deleted from, a group forreasons of convenience and/or patentability. When any such inclusion ordeletion occurs, the specification is herein deemed to contain the groupas modified thus fulfilling the written description of all Markushgroups used in the appended claims.

Each of the appended claims defines a separate invention, which forinfringement purposes is recognized as including equivalents to thevarious elements or limitations specified in the claims. Depending onthe context, all references below to the “invention” may in some casesrefer to certain specific embodiments only. In other cases it will berecognized that references to the “invention” will refer to subjectmatter recited in one or more, but not necessarily all, of the claims.

Various terms are used herein. To the extent a term used in a claim isnot defined, it should be given the broadest definition persons in thepertinent art have given that term as reflected in printed publicationsand issued patents at the time of filing.

The term “spring” used herein refers to an elastic object that ondeformation stores mechanical energy, and includes, besides a metallichelical spring, rubber or plastic designs that behave like metallichelical springs to store energy and provide biasing force on beingdeformed.

Embodiments explained herein relate to a single solenoid double actuatordevice, which actuates two actuators at two different current values. Inanother aspect, the two actuator plungers of the disclosed device arearranged in parallel configuration spaced apart from each other, therebyovercoming limitation of the known devices that require the two actuatorplungers to be arranged in collinear fashion, which may not be possiblein certain applications.

It is to be appreciated that while various embodiments explained hereinshow the pull plunger mechanism where in energized condition actuatorsare actuated (pulled up) and dropped down with spring load, it would beevident to those skilled in that art that concepts of the presentdisclosure can be used to derive mechanisms where actuators is in pushplunger mechanism where in energized condition actuators are pushed downand pushed up with spring load.

In one embodiment, the device is configured such that passing a currentthrough the single coil creates a single magnetic path through the twoactuator plungers, and the two actuator plungers are biased by biasingforces such that one of them gets actuated at a lower current value andthe other actuator plunger gets actuated at a higher current value.

The single magnetic path through the two actuator plungers is achievedby a pair of magnetic paths, having an upper magnetic path and a lowermagnetic path, configured on upper side and lower side respectively ofthe two actuator plungers such that the single magnetic path runsthrough the first actuator plunger, the upper magnetic path, the secondactuator plunger and the lower magnetic path.

In another embodiment, the device is configured such that passing acurrent through the single coil creates two magnetic paths such that oneof the actuator plungers is in only one of the two magnetic paths, andthe other actuator plunger is both the magnetic paths. The actuatorplunger which is part of both the magnetic paths, is subjected to highermagnetic force and therefore gets actuated at lower current, and theother actuator plunger, which is part of only one of the two magneticpaths, is subjected to lower magnetic force and therefore gets actuatedat higher current.

The two magnetic paths are achieved by providing a connecting portionbetween the upper magnetic path and the low magnetic path, which islocated between the second actuator plunger and the solenoid winding.The connecting portion provides a secondary magnetic path through thefirst actuator plunger, a part of the upper magnetic path, theconnecting portion and a part of the lower magnetic path.

Referring now to FIG. 1, the disclosed single solenoid double actuatordevice 100 includes a solenoid winding 102 wound around a tubular shapedbobbin 104 having an opening. The opening defines an axis A-A of thesolenoid winding 102. A first actuator plunger 106 (Also referred to asfirst actuator or as first plunger, and all these terms usedinterchangeably hereinafter) may be configured through the opening ofthe solenoid winding 102 for linear movement along the axis A-A betweenan actuated position and a dropped position. The actuated position ofthe first actuator plunger 106 may correspond to a position in which oneend, such as an upper end, of the first actuator 106 makes a contactwith a static pole, such as static pole 108 located coaxially above thefirst actuator 106, and the dropped position may correspond to aposition in which the upper end of the first actuator 106 is not incontact with the static pole 108, i.e. a gap, such as gap 110 shown inFIG. 1, exists between the upper end of the first actuator 106 and thestatic pole 108.

The first actuator 106 during its linear motion between the droppedportion and the actuated position may be guided within a first guide 112located within the bobbin 104 aligned along the axis A-A. Further, thefirst actuator 106 may be biased to remain in the dropped position by abiasing force, referred to as first biasing force.

The biasing force may be provided by a first spring located between acollar, such as collar 114 of the first actuator 106 and the first guide112 such that a biasing force, referred to as first biasing force, isapplied to the first actuator 106 to keep it in the dropped position,i.e. away from the static pole 108.

The device 100 includes a second actuator plunger 120 (Also referred toas second actuator or as second plunger, and all these terms usedinterchangeably hereinafter), which may be arranged through an annularshaped second actuator guide 122 for linear movement along an axis B-B,referred to as second actuator axis. The second actuator plunger 120 maybe arranged such that the second actuator axis B-B and is spaced fromthe axis A-A of the solenoid winding 102, and may be substantiallyparallel.

It is to be appreciated that while the exemplary illustrations show thataxis A-A and axis B-B are parallel, it is possible to configure thedevice such that the two actuators plungers 106 and 120 are inconfiguration other than parallel, such as an angular configurationwherein the axis B-B is at angel to the axis A-A, and all suchvariations are well within the scope of the present disclosure withoutany limitations whatsoever.

The device may further include a pair of magnetic paths having an uppermagnetic path 130 located at an upper end of the solenoid winding 102and the second guide 122, and a lower magnetic path 132 located at alower end of the solenoid winding 102 and the second guide 122. Thus,the first actuator 106 and the second actuator 120 may be arrangedbetween the upper magnetic path 130 and the lower magnetic path 132 suchthat when a current is passed through the solenoid winding 102, amagnetic field is setup along a magnetic path through the first actuator106, the upper magnetic path 130, the second actuator 120 and the lowermagnetic path 132.

The upper magnetic path 130 and the lower magnetic path 132 can be anyof a plate, profiles like rod, pipe, tubes etc. made of a ferro-magneticmaterial.

The second actuator 120 may linearly move between an actuated positionand a dropped position, and may be biased by a second biasing force toremain in the dropped position. The actuated position of the secondactuator plunger 120 may correspond to a position in which one end, suchas an upper end, of the second actuator 120 makes a contact with theupper magnetic path 130, and the dropped position may correspond to aposition in which the upper end of the second actuator 120 is not incontact with the upper magnetic path 130, i.e. a gap, such as gap 126shown in FIG. 1, exists between the upper end of the second actuator 120and the upper magnetic path 130.

The second actuator 120 may be biased to remain in the dropped positionby a second spring 124 configured between the second actuator 120 andthe upper magnetic path 130 such that the second spring 124 exerts abiasing force, referred to as second biasing force, on the secondactuator 120 in the direction towards the lower magnetic path 132.

The first biasing force exerted by the first spring 116 on the firstactuator 106, the second biasing force exerted by the second spring 124on the second actuator 120 may differ and depending on other factors,such as the magnetic path, or configuration of the actuator plungers 106and 120, the actuator subjected to a lower biasing force or subjected tohigher magnetic force, may get actuated first to move to the actuatedposition when a gradually increasing current is applied to the solenoidwinding 102. The other actuator that is subjected to a higher biasingforce, or lower magnetic force, may get actuated at a higher currentthrough the solenoid winding 102.

In an example application, the first actuator 106 may get actuated firstat a first current value overcoming the first biasing force which may belower than the second biasing force, and the second actuator 120 may getactuated subsequently at a higher second current value overcoming thesecond biasing force which may be higher than the first biasing force.

In an example application, the first actuator 106 may get actuated at acurrent of 1 Amp, and the second actuator 120 may get actuated at acurrent of 3.27 Amps. The solenoid winding may have a resistance of2.55Ω and the required current values for actuation of the firstactuator 106 and the second actuator 120 may be achieved by applicationof voltage of 2.7 V and 9.3V respectively.

As is known in the art, force of a plunger of as a result of a currentpassing through the coil depends on stroke L (distance plunger of theactuator needs to move), permeability of the actuator plunger (μ) whichdepends on material of the plunger, area exposed (A) to the magneticfield, current (I) passing through the solenoid coil and number of turns(N) in the solenoid coil, General formula which is used for this is asbelow:

? ?indicates text missing or illegible when filed

where μ₀ is permeability of air.

Therefore, the actuators may be configured, by selecting materialshaving different permeability for the plungers of the two actuator, anddifferent geometry, to experience different forces for same currentapplied to the solenoid, thereby controlling which of the two actuatorsgets actuated first at lower current, followed by other actuator withincrease of current. Besides these parameters, stroke of the respectiveplungers and biasing force on the plungers, which is controlled by therespective biasing springs, shall play important role.

In an alternate embodiment, the actuation of one of the two actuatorplungers at a lower current and actuation of the other actuator plungerat a higher current may be achieved by providing two magnetic paths. Oneof the two actuator plungers may be part of both the magnetic paths butthe other actuator plunger is part of only one of the two magneticpaths. The actuator plunger which is part of two magnetic paths issubjected to higher magnetic force, and therefore, may get actuated atlower current applied through the solenoid winding. The other actuatorplunger being part of only one of the two magnetic paths, is subjectedto lower magnetic force, and therefore, shall get actuated at highercurrent through the solenoid winding.

FIG. 3 illustrates an exemplary representation of the single solenoidbased double actuator device 300 having two magnetic paths, wherein theupper magnetic path 130 and the lower magnetic path 132 are coupled toeach other by a connecting portion 302 located between the secondactuator plunger 120 and the solenoid winding 102. The connectingportion 302 may provide a secondary magnetic path 304 through the firstactuator plunger 106, a part of the upper magnetic path 130, theconnecting portion 302 and a part of the lower magnetic path 132. Asbefore, earlier magnetic path, referred to as primary magnetic path,through the first actuator 106, the upper magnetic path 130, the secondactuator 120 and the lower magnetic path 132 also exists, and passesthrough both the actuator plungers 106 and 120, as against the secondarymagnetic path that passes through only the first actuator plunger 106.

Therefore, the first actuator plunger 106 is part of both the magneticpaths, i.e. the primary magnetic path 118 and the secondary magneticpath 304, but the second actuator plunger 120 is part of only theprimary magnetic paths 118. The first actuator plunger 106 being part ofthe two magnetic paths 118 and 304 is subjected to higher magneticforce, and therefore may get actuated at lower current through thesolenoid winding 102, and the second actuator plunger 120 being part ofonly the primary magnetic path 118, is subjected to lower magnetic forceand shall get actuated at higher current through the solenoid winding102.

When the current through the solenoid winding 102 exceeds the firstcurrent value, only the first actuator plunger 106 may move to thecorresponding actuated position overcoming the corresponding biasingforce on account of higher magnetic force from combination of magneticfields through the primary magnetic path 118 and the secondary magneticpath 304, with the second actuator plunger 120 remaining unmoved in thedropped position due to weaker magnetic force from the magnetic fieldthrough the lone secondary magnetic path 304.

When the current through the solenoid winding 102 exceeds the secondcurrent value, the second actuator plunger 120 may also move to thecorresponding actuated position overcoming the corresponding biasingforce on account of magnetic force from comparatively weaker magneticfield through the secondary magnetic path 304.

In another embodiment, a single solenoid based double actuator device isdisclosed, wherein the axis of the solenoid is separated from axis offirst actuator and the second actuator. Referring to FIG. 4, thedisclosed single solenoid based double actuator device 400 having theaxis of the solenoid separated from axis of first actuator and thesecond actuator includes a solenoid winding 402 wound around a bobbin412 having an opening along an axis of the solenoid winding and aconnecting static pole 440 located along the axis of the solenoidwinding 402 through the opening. A pair of magnetic paths is providedhaving an upper magnetic path 430 located at an upper end of theconnecting static pole 440, and a lower magnetic path 432 located at alower end of the connecting static pole 440.

A first actuator plunger 404 is arranged through a first guide 406 alongwith a static pole 408 for linear movement between an actuated positionand a dropped position along a first actuator axis. A second actuatorplunger 420 is arranged through a second guide 422 for linear movementbetween an actuated position and an dropped position along a secondactuator axis. The first actuator plunger 404 is biased by a firstspring 416 that provides a first biasing force, to remain in the droppedposition, and the second actuator plunger 430 is biased by a secondspring 424 that provides a second biasing force to keep the secondactuator 420 in corresponding dropped position.

The first actuator plunger 404 and the second actuator plunger 420 maybe arranged between the upper magnetic path 430 and the lower magneticpath 432 such that the first actuator axis and the second actuator axisare spaced apart from the axis of the solenoid winding 402.

In an aspect, the connecting static pole 440, the upper magnetic path430, the static pole 408, the first actuator plunger 404, and the lowermagnetic path 432 provide a first magnetic path 442 for a magnetic fieldcreated as a result of passing of a current through the solenoid winding402, and the connecting static pole 440, the upper magnetic path 430,the second actuator plunger 420, and the lower magnetic path 432 providea second magnetic path 418 for the magnetic field created as a result ofpassing of a current through the solenoid winding.

FIG. 4 shows an unactuated position of the device 400 when no current issupplied to the solenoid winding 402, and both the first actuatorplunger 404 and the second actuator plunger 420 are in theircorresponding dropped positions. The dropped positions of the firstactuator plunger 404 and the second actuator plunger 420 are shown by afirst gap 410 between the first actuator plunger 404 and the static pole408, and a second gap 426 between the second actuator plunger 420 andthe upper magnetic path 320.

In an aspect, the first biasing force, the second biasing force, thefirst magnetic path 442 and the second magnetic path 418 are configuredsuch that when the current through the solenoid winding 402 exceeds afirst current value, one of the first actuator plunger and the secondactuator plunger is moved to the corresponding actuated positionovercoming the corresponding biasing force to close the first gap 410 asshown in FIG. 5A, where the first actuator plunger 404 is shown in theactuated position indicated by absence of the first gap 408, whereas thesecond actuator plunger 420 is still in dropped position indicated bythe second gap 426. When the current through the solenoid winding 402exceeds a second current value, which is higher than the first currentvalue, other of the second actuator plunger 420 is also moved to thecorresponding actuated position overcoming the corresponding biasingforce. This position is shown in FIG. 5B, where both the first actuatorplunger 404 and the second actuator plunger 420 are shown in theactuated position indicated by absence of the first gap 408 and thesecond gap 426.

In an embodiment, in any of the configurations of the single solenoidbased double actuator device 100, 300 and 400 depicted in FIGS. 1, 3 and4 respectively, the biasing force on one of the two or both the actuatorplungers 106 and 120 may be applied by a combination of a permanentmagnet, such as a first permanent magnet and the second permanentmagnet, and a spring, such as a first spring and the second spring,respectively configured with the corresponding actuators. The permanentmagnets may below intensity permanent magnets, and the magnet and thecorresponding spring may be configured such that a net biasing force,either from the spring or the permanent magnet, works on thecorresponding actuator plunger to keep it in the dropped position. Whena current is applied to the solenoid 102, the generated magnetic fieldmay, depending on configuration, supplement or counter the magneticfield from the permanent magnet to move the actuator plunger to theactuated position.

As can be appreciated that there are many ways to configure thepermanent magnet and the spring on one or both of the actuators toachieve actuation of one of the two actuators at lower current and theother actuator at a higher current. For example, the first permanentmagnet and the second permanent magnet may be configured such that therespective magnetic fields are in opposite directions, in which case themagnetic field generated as a result of passing of a current through thesolenoid winding shall add to the magnetic field of the one of the twopermanent magnets and shall nullify the magnetic field of the other ofthe two permanent magnets. When a current exceeding the first currentvalue is applied through the solenoid winding in a first direction oneof the first actuator plunger and the second actuator plunger shall moveto the corresponding actuated position. On the other hand, when acurrent exceeding the second current value is applied through thesolenoid winding in a second direction that is opposite the firstdirection, other of the first actuator plunger and the second actuatorplunger shall be moved to the corresponding actuated position. When thecurrent in the second direction is further increase, both the actuatorplungers are moved to the actuated positions.

Thus, using above configuration, it is possible to achieve threeindependent combinations for positions of the two actuator plungers. Thethree combinations being a first combination in which only the firstactuator is moved to the actuated position, which is on application of acurrent in the first direction; s second combination in which only thesecond actuator plunger is moved to the actuated position, which is onapplication of a low current in the second direction; and the thirdcombination in which both the first and the second actuator plungers aremoved to the actuated position, which is on application of a highercurrent in the second direction. These three combinations are besides acombination in which both the actuation plungers are in droppedcondition.

Advantage of the proposed concept, implemented in different manners asdescribed by different embodiments as above, is lower cost as need fortwo separate solenoids, primary and secondary, is eliminated. Alsoplungers 106 and 120 of the two actuators may be arranged in non-coaxialconfiguration, i.e. they need not have linear movement along a commonaxis, and can be arranged in parallel configuration or at an angle.

In yet another embodiment applicable to any of the configurations of thesingle solenoid based double actuator device 100, 300 and 400 depictedin FIGS. 1, 3 and 4 respectively, the actuator plungers may beconfigured for latching in the actuated position so that the appliedcurrent may be switched off after the actuators have been actuated bypulsed current, thereby reducing power consumption. In this scenario,the permanent magnets may be selected such that they have enoughmagnetic force such that it holds the corresponding plunger once liftedagainst spring load to maintain the latching.

In an exemplary implementation, a first magnet (not shown) is used withthe first plunger 106 in combination of a first spring such that a netforce from the first spring, referred to as first biasing force, biasesthe first plunger 106 in the dropped position. A second magnet (notshown) is used with the second plunger 120 in combination with a secondspring such that a net force, referred to as second biasing force, fromthe second spring biases the second plunger 120 in the dropped position.The first magnet may have a lower strength compare to the second magnetbut enough to hold the first plunger 106 once lifted, and the secondmagnet is able to hold the second plunger 120 once lifted, against theirrespective spring loads.

Direction of the first magnet and the second magnet may be keptopposite, such that when a supply pulse (referred to as first pulse) ofa first current value is given to the solenoid winding 102 in a firstdirection, the first plunger 106 moves to the actuated position onaccount of the generated electro-magnetic field supporting the magneticfield from the first magnet to overcome the net biasing force on thefirst plunger 106, and is held in the actuated position by the latchingaction even after the current stops. The second plunger 120 does not getactuated on application of current in the first direction becausedirection of the generated electro-magnetic field is opposite tomagnetic field of the second magnet, thereby adding to the biasing forceto keep the second plunger 120 in the dropped position.

When a pulse of the second current value (referred to as second pulse),which is lower than the first current value but in a second direction,which is opposite the first direction, is supplied to the solenoidwinding 102, an electro-magnetic field in opposite direction matchingthe direction of magnetic field of the second magnet is generated, andgets added to the magnetic field of the second magnet. The enhancedmagnetic field may provide adequate magnetic force to the second plunger120 to overcome the second biasing force. The second current value beinglower than the first current value or the current required to unlatchthe first plunger, the first plunger remains in the actuated position.When the second pulse stops, the second plunger remains in the actuatedposition because of the latching action. Thus, both the first plungerand the second plunger attain corresponding actuated positions.

In order to move the actuator plungers 106 and 120 back to the droppedpositions, a pulse of high current in the second direction may be givenso that the first plunger 106 gets release from the latched actuatedposition by nullifying the magnetic field of the first magnet, therebyenhancing the force from the first spring and moving the first plunger106 to the dropped position. Likewise, the second plunger 120 can beunlatched and moved to the dropped position by giving low current pulsein the first direction. The requirement of the pulsed currents, theirdirection and position of the plungers is summarized in the below table:

Current pulse Plunger movement Direction Strength First plunger Secondplunger First direction High Moves to actuated Remains in droppedposition position Second direction Low Remains in actuated Moves toactuated position position Second direction High Moves to droppedRemains in actuated position position First direction low Remains indropped Moves to dropped position position

In the proposed embodiment, the Double actuator device requires onlypulses of current and not continuous current to change the status of thetwo actuators, which reduces power consumption. Besides in situations ofpower failure the system does not reset and maintains the last position.

Thus, the present disclosure provides a single solenoid double actuatordevice, which actuates two actuator plungers at two different currentvalues. The disclosed device overcomes drawback of known single solenoiddouble actuator devices that require the two actuator plungers to bearranged in collinear fashion. An embodiment of the disclosed deviceallows the device to be actuated by current pulses, thereby reducingpower consumption and eliminating need to reset the device in instancesof power failure. Further, the disclosed concept can be used toconfigure devices having more than two actuators.

While the foregoing describes various embodiments of the invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof. The scope of the invention isdetermined by the claims that follow. The invention is not limited tothe described embodiments, versions or examples, which are included toenable a person having ordinary skill in the art to make and use theinvention when combined with information and knowledge available to theperson having ordinary skill in the art.

Advantages of the Invention

The present disclosure provides a single solenoid double actuator devicethat overcomes drawback of known devices.

The present disclosure provides a single solenoid double actuator devicethat does not require the two actuators to be in collinear arrangement.

The present disclosure provides a single solenoid double actuator devicethat allows actuation of the two actuators in sequential manner orindependently.

The present disclosure provides a single solenoid double actuator devicethat uses a single magnetic path to actuate the two actuators.

The present disclosure provides a single solenoid double actuator devicethat consumes less power by enabling actuation of the two actuators bycurrent pulses.

We claim:
 1. A single solenoid based double actuator device, the devicecomprising; a solenoid winding having an opening along an axis of thesolenoid winding; a first actuator plunger configured through theopening of the solenoid winding for linear movement along the axis ofthe solenoid winding between an actuated position and a dropped positionand being biased by a first biasing force to remain in the droppedposition; a pair of magnetic paths comprising an upper magnetic pathconfigured at an upper end of the solenoid winding, and a lower magneticpath configured at a lower end of the solenoid winding; a secondactuator plunger configured for linear movement along a second actuatoraxis between an actuated position and an dropped position and biased bya second biasing force to remain in the dropped position; wherein thefirst actuator plunger, the upper magnetic path, the second actuatorplunger and the lower magnetic path provide a magnetic path for amagnetic field created as a result of passing of a current through thesolenoid winding; and wherein the first biasing force, the secondbiasing force and the magnetic path is configured such that when thecurrent through the solenoid winding exceeds a first current value, oneof the first actuator plunger and the second actuator plunger is movedto the corresponding actuated position overcoming the correspondingbiasing force, and when the current through the solenoid winding exceedsa second current value, which is higher than the first current value,other of the first actuator plunger and the second actuator plunger isalso moved to the corresponding actuated position overcoming thecorresponding biasing force.
 2. The device as claimed in claim 1,wherein the first biasing force is higher than the second biasing force,and when the current through the solenoid winding exceeds the firstcurrent value, the first actuator plunger is moved to the correspondingactuated position overcoming the first biasing force, and when thecurrent through the solenoid winding exceeds the second current value,the second actuator plunger is moved to the corresponding actuatedposition overcoming the second biasing force.
 3. The device as claimedin claim 1, wherein the first biasing force is provided by a firstspring configured between a collar on the first actuator plunger and thefirst guide to bias the first actuator plunger in a direction towardsthe lower magnetic path.
 4. The device as claimed in claim 3, whereinthe second biasing force is provided by a second spring configuredbetween the second actuator plunger and the upper magnetic path to biasthe second actuator plunger in the direction towards the lower magneticpath.
 5. A single solenoid based double actuator device, the devicecomprising; a solenoid winding having an opening along an axis of thesolenoid winding; a first actuator plunger configured through theopening for linear movement along the axis of the solenoid windingbetween an actuated position and an dropped position and being biased bya first biasing force to remain in the dropped position; a pair ofmagnetic paths comprising an upper magnetic path configured at an upperend of the solenoid winding, and a lower magnetic path configured at alower end of the solenoid winding; a second actuator plunger arrangedconfigured for linear movement along a second actuator axis between anactuated position and an dropped position and being biased by a secondbiasing force to remain in the dropped position; wherein the firstactuator plunger, the upper magnetic path, the second actuator plungerand the lower magnetic path provide a primary magnetic path for amagnetic field created as a result of passing of a current through thesolenoid winding; and wherein the upper magnetic path and the lowermagnetic path are coupled to each other by a connecting portion locatedbetween the second actuator plunger and the solenoid winding, theconnecting portion providing a secondary magnetic path through the firstactuator plunger, a part of the upper magnetic path, the connectingportion and a part of the lower magnetic path; and wherein the firstbiasing force, the second biasing force and the primary magnetic pathand the secondary magnetic path are configured such that when thecurrent through the solenoid winding exceeds a first current value, thefirst actuator plunger is moved to the corresponding actuated positionovercoming the corresponding biasing force, and when the current throughthe solenoid winding exceeds a second current value, which is higherthan the first current value, the second actuator plunger is also movedto the corresponding actuated position overcoming the correspondingbiasing force;
 6. The device as claimed in claim 5, wherein when thecurrent through the solenoid winding exceeds the first current value,only the first actuator plunger is moved to the corresponding actuatedposition overcoming the corresponding biasing force on account of highermagnetic force from combination of magnetic fields through the magneticpath formed by the first actuator plunger, the upper magnetic path, thesecond actuator and the lower magnetic path, and the secondary magneticpath formed by the first actuator plunger, a part of the upper magneticpath, the connecting portion and a part of the lower magnetic path. 7.The device as claimed in claim 6, wherein when the current through thesolenoid winding exceeds the second current value, the second actuatorplunger is also moved to the corresponding actuated position overcomingthe corresponding biasing force on account of magnetic force fromcomparatively weaker magnetic field through the secondary magnetic pathformed by the first actuator plunger, a part of the upper magnetic path,the connecting portion and a part of the lower magnetic path.
 8. Asingle solenoid based double actuator device, the device comprising; asolenoid winding having an opening along an axis of the solenoidwinding; a connecting static pole provided through the opening of thesolenoid winding; a pair of magnetic paths comprising an upper magneticpath configured at an upper end of the solenoid winding and coupled toan upper end of the connecting static pole, and a lower magnetic pathconfigured at a lower end of the solenoid winding and coupled to a lowerend of the connecting static pole; a first actuator plunger configuredbetween the upper magnetic path and the lower magnetic path for linearmovement along an first actuator axis between an actuated position andan dropped position and being biased by a first biasing force to remainin the dropped position; and a second actuator plunger configuredbetween the upper magnetic path and the lower magnetic path for linearmovement along a second actuator axis between an actuated position andan dropped position and being biased by a second biasing force to remainin the dropped position; wherein the first actuator axis and the secondactuator axis are spaced apart from the solenoid axis; wherein the firstactuator plunger, the static pole, the upper magnetic path, theconnecting static pole, and the lower magnetic path provide a firstmagnetic path for a magnetic field created as a result of passing of acurrent through the solenoid winding; and the second actuator plunger,the upper magnetic path, the connecting static pole, and the lowermagnetic path provide a second magnetic path for the magnetic fieldcreated as a result of passing of a current through the solenoidwinding; and wherein the first biasing force, the second biasing force,the first magnetic path and the second magnetic path are configured suchthat when the current through the solenoid winding exceeds a firstcurrent value, one of the first actuator plunger and the second actuatorplunger is moved to the corresponding actuated position overcoming thecorresponding biasing force, and when the current through the solenoidwinding exceeds a second current value, other of the first actuatorplunger and the second actuator plunger is also moved to thecorresponding actuated position overcoming the corresponding biasingforce.
 9. The device as claimed in claim 6, wherein the solenoid axis islocated between the first actuator axis and the second actuator axis.10. The device as claimed in claim 8, wherein the first biasing force isprovided by a first spring configured with the first plunger, and thesecond biasing force is provided by a second spring configured with thesecond plunger, and wherein the second current value is higher than thefirst current value and in the same direction.
 11. The device as claimedin claim 8, wherein the first biasing force is provided by a combinationof a first permanent magnet and a first spring configured with the firstactuator plunger, and the second biasing force is provided by acombination of a second permanent magnet and a second spring configuredwith the second actuator plunger.
 12. The device as claimed in claim 11,wherein the magnetic field generated as a result of passing of a currentthrough the solenoid winding, either supports or nullifies magneticfields of the first permanent magnet and the second permanent magnet tochange the net biasing force on the corresponding actuator plunger suchthat when the current through the solenoid winding exceeds a firstcurrent value, one of the first actuator plunger and the second actuatorplunger is moved to the corresponding actuated position, and when thecurrent through the solenoid winding exceeds a second current value,which is higher than the first current value and in same direction asthe first current value, other of the first actuator plunger and thesecond actuator plunger is also moved to the corresponding actuatedposition.
 13. The device as claimed in claim 11, wherein the firstpermanent magnet and the second permanent magnet are configured suchthat the respective magnetic fields are in opposite directions, and themagnetic field generated as a result of passing of a current through thesolenoid winding adds to the magnetic field of the one of the twopermanent magnets and nullifies the magnetic field of the other of thetwo permanent magnets; and wherein when a current exceeding the firstcurrent value is applied through the solenoid winding in a firstdirection, one of the first actuator plunger and the second actuatorplunger is moved to the corresponding actuated position, and when acurrent exceeding the second current value is applied through thesolenoid winding in a second direction that is opposite the firstdirection, the other of the first actuator plunger and the secondactuator plunger is moved to the corresponding actuated position; andwherein when the current in the second direction is increased, both thefirst actuator plunger and the second actuator plunger are moved to thecorresponding actuated positions.
 14. A single solenoid based doubleactuator device, the device comprising; a solenoid winding having anopening along an axis of the solenoid winding; a first actuator plungerconfigured through the opening for linear movement along the axis of thesolenoid winding between an actuated position and an dropped positionand being biased by a first biasing force to remain in the droppedposition; a pair of magnetic paths comprising an upper magnetic pathconfigured at an upper end of the solenoid winding, and a lower magneticpath configured at a lower end of the solenoid winding; a secondactuator plunger configured for linear movement along a second actuatoraxis between an actuated position and an dropped position and beingbiased by a second biasing force to remain in the dropped position;wherein the first actuator plunger, the upper magnetic path, the secondactuator plunger and the lower magnetic path provide a magnetic path fora magnetic field generated as a result of passing of a current throughthe solenoid winding; and wherein the first biasing force is provided bya combination of a first permanent magnet and a first spring configuredwith the first actuator plunger, and the second biasing force isprovided by a combination of a second permanent magnet and a secondspring configured with the second actuator plunger; wherein the magneticfield generated as a result of passing of a current through the solenoidwinding, either supports or nullifies magnetic fields of the firstpermanent magnet and the second permanent magnet to change the netbiasing force on the corresponding actuator plunger such that when thecurrent through the solenoid winding exceeds a first current value, oneof the first actuator plunger and the second actuator plunger is movedto the corresponding actuated position, and when the current through thesolenoid winding exceeds a second current value, which is higher thanthe first current value other of the first actuator plunger and thesecond actuator plunger is also moved to the corresponding actuatedposition.
 15. The device as claimed in claim 14, wherein the firstpermanent magnet and the second permanent magnet are configured suchthat the respective magnetic fields are in opposite directions, and themagnetic field generated as a result of passing of a current through thesolenoid winding adds to the magnetic field of the one of the twopermanent magnets and nullifies the magnetic field of the other of thetwo permanent magnets; and wherein when a current exceeding the firstcurrent value is applied through the solenoid winding in a firstdirection, one of the first actuator plunger and the second actuatorplunger is moved to the corresponding actuated position, and when acurrent exceeding the second current value is applied through thesolenoid winding in a second direction that is opposite the firstdirection, the other of the first actuator plunger and the secondactuator plunger is moved to the corresponding actuated position; andwherein when the current in the second direction is increased, both thefirst actuator plunger and the second actuator plunger are moved to thecorresponding actuated positions.
 16. A single solenoid based doubleactuator device, the device comprising; a solenoid winding having anopening along an axis of the solenoid winding; a first actuator plungerconfigured through the opening for linear movement along the axis of thesolenoid winding between an actuated position and an dropped positionand being biased by a first biasing force to remain in the droppedposition; a pair of magnetic paths comprising an upper magnetic pathconfigured at an upper end of the solenoid winding, and a lower magneticpath configured at a lower end of the solenoid winding; a secondactuator plunger configured for linear movement along a second actuatoraxis between an actuated position and an dropped position and beingbiased by a second biasing force to remain in the dropped position;wherein the first actuator plunger, the upper magnetic path, the secondactuator plunger and the lower magnetic path provide a magnetic path fora magnetic field generated as a result of passing of a current throughthe solenoid winding; and wherein the first biasing force is provided bya combination of a first permanent magnet and a first spring configuredwith the first actuator plunger, and the second biasing force isprovided by a combination of a second permanent magnet and a secondspring configured with the second actuator plunger; the two permanentmagnets and the corresponding springs being configured such thatmagnetic force on the first actuator plunger and the second actuatorplunger from the respective permanent magnets partly nullifies the forcefrom the corresponding springs; wherein the magnetic field generated asa result of passing of a current through the solenoid winding, eithersupports or nullifies magnetic fields of the first permanent magnet andthe second permanent magnet to change the net biasing force on thecorresponding actuator plunger such that when the current through thesolenoid winding exceeds a first current value, one of the firstactuator plunger and the second actuator plunger is moved to thecorresponding actuated position, and when the current through thesolenoid winding exceeds a second current value, other of the firstactuator plunger and the second actuator plunger is also moved to thecorresponding actuated position; and wherein each of the first actuatorplunger and the second actuator plunger and the corresponding permanentmagnets are configured for latching of the first actuator plunger andthe second actuator plunger in the corresponding actuated positions suchthat after the current through the solenoid winding is stopped, thefirst actuator plunger and the second actuator plunger remain in theactuated position thereby enabling actuation of the device by applyingcurrent pulses.
 17. The device as claimed in claim 16, wherein the firstpermanent magnet and the second permanent magnet are configured suchthat the respective magnetic fields are in opposite directions, and themagnetic field generated as a result of passing of a current through thesolenoid winding adds to the magnetic field of the one of the twopermanent magnets and nullifies the magnetic field of the other of thetwo permanent magnets; and wherein one of the first actuator plunger andthe second actuator plunger is moved to the corresponding actuatedposition, and when the current pulse exceeding the first current valueis applied through the solenoid winding in a first direction, and theother of the first actuator plunger and the second actuator plunger isalso moved to the corresponding actuated position when the current pulseexceeding the second current value is applied through the solenoidwinding in a second direction that is opposite the first direction. 18.The device as claimed in claim 16, wherein the second current value islower than the first current value so that the first actuator plungerdoes not move to the dropped position.